Who among us can honestly say they have never called Channel 4 during Richard & Judy and screamed down the line: "I'm truly sick of looking at Judy's cleavage!"?

Yes, we've all done it. Haven't we? Oh. Well, no need to come on all holier than thou because lots of people have and the above is an actual example from the Channel 4 duty officers' log. Judy's décolletage causes a lot of consternation.

Another genuine example: "Judy has been wearing those plunging necklines lately. It is most unpleasant to see, especially when sitting with the grandchildren."

And another: "Tell Judy to use a safety pin. Her cleavage is unbelievable. She must cover up, she is not young and pert any more."

Received wisdom has it that the British don't complain. We chow down on any old crap put in front of us in a "restaurant" without so much as a squeak of protest. We stand around for hours on crowded platforms waiting for trains that never turn up and pay handsomely for the privilege.

But sit us in front of a TV with a phone by our side and a red mist descends, a red mist suffused with the dull glow of barking lunacy.

Witness the individual who rang the BBC furious that a news item about commercial whaling in Iceland did not make it sufficiently clear that the whaling was occurring in the sea around Iceland the country and not the frozen food retailer of the same name.

Or the irate RI:SE viewer who demanded of the C4 duty officer: "Why are your presenters putting their feet on the furniture all the time when British Rail are struggling to get people to stop this sort of behaviour?"

Or the woman who called Five when The Wright Stuff was featuring a discussion about the sexual behaviour of working-class kids, to argue forcefully that Camilla Parker Bowles was to blame for the promiscuity of some council estate youngsters "because it is alleged that she has sex".

How about the bloke who calls ITV every time it pours down just to let them know that he "does not like the rain"?

Lots of people who watch the telly are mad. It's not known whether TV drives them insane or whether they watch the box because they are already totally Tonto, but bonkers they most certainly are.

The BBC receives around 1.1 million unsolicited contacts a year. The vast majority are enquiries but around 7% are complaints - that's approximately 211 a day. Most of those will be concerns about perceived political bias, explicit scenes of sex or violence and so on. But, apart from the obvious, it's very difficult to predict what will spark calls from the public.

After one recent BBC documentary about the second world war, an enraged licence-holder called the Beeb to complain that the film "had shown Hitler in a bad light".

An episode of EastEnders prompted a complaint that it showed people drinking from bottles rather than glasses and was therefore responsible for teenagers "acting like tramps".

A feature film shown on the BBC in which the word "fuck" was used 159 times prompted fewer complaints than an episode of The Archers in which a character said "piss".

However, duty officers are aware that rescheduling always provokes fury. When Crossroads was removed in favour of rolling news coverage of the events of 9/11, the ITV phones went into meltdown. This would be pathetic enough if it had been a protest about the removal of The Sopranos or The Simpsons - but Crossroads?

Similarly, in 1990, when The Antiques Roadshow was dropped for live coverage of the release of Nelson Mandela, more than 500 disgusted antiques lovers called the BBC to register their displeasure at being forced to watch history in the making rather than some duffer asking how much he should insure his complete set of Rupert the Bear annuals for.

Bruce Vander is an operations manager for BBC Information. "The thing about unsolicited calls is that you have no idea what the next one is going to be about," he says. "It might be about a television programme that was on 20 years earlier, or it could be about what was said on the news 30 seconds ago. And you have to be equally prepared for abuse or praise."

Channel 4 receives a quarter of a million emails and complaints each year, of which "a fraction" are whinges.

"We tend to get complaints about what our presenters wear," says a spokesman. "Specifically, Richard and Judy's clothes, hair and makeup, as well as Carol Vorderman's outfits on Countdown. Before he departed, Graham Norton's suits were also a source of several calls."

Any right-thinking person would be moved to anger by Norton's clobber but poor Richard and Judy? What have they ever done to attract such opprobrium?

"Tonight I am really disillusioned," sighed one complainant. "Judy was laughing at Mrs Beckham's hat. She should have shown more decorum. I thought Judy was a lady. I won't be watching any more."

"I do wish Richard wouldn't keep crossing his legs so that all I can see is the sole of his shoe," said another. "It's not cool and it's not trendy."

Family Affairs, Five's flagship soap, comes in for a fair amount of flack. Someone identifying herself as the Prophetess Esther contacted the broadcaster to tell them that God approved of an incest storyline but also wanted to point out that when one-night stands don't work out, "people turn to drugs, nicotine, cocaine and alcohol, prostitution and threesomes, vibrators and material supplements, then start jumping from roofs."

Another caller was disgusted that "Nikki has been living in that house for quite some time now and she still has no stairway carpeting."

There is a very thin line between the eccentricity of some callers and the genuine mental health issues of others. John Reith himself, the founding father of the BBC, noted: "Periodically, letters come in, one per thousand or two, which make one doubt the sanity of the correspondent - in fact, there is little room for anything other than doubt."

One BBC duty officer was very disturbed when the woman on the end of the line who had been complaining about the shrieking emitted by her TV revealed that the wailing continued through the night. When the TV was turned off.

A Channel 4 duty officer took a call when Johnny Vaughan was interviewing Tom Cruise on the Big Breakfast. The caller wanted the duty officer to warn Vaughan that Cruise was an alien and would take over the presenter's body if he got too close.

Some complaints are almost too good to be true: they have a whiff of the urban myth about them. Ed Harris in his history of the BBC complaints department, Not In Front Of The Telly, relates the story of the caller who wanted to make an offer on one of the vehicles in the used car lot in EastEnders.

When told they were only props and not actually for sale he demanded to talk to a supervisor, fuming that the BBC was guilty of "stifling free enterprise".

But it's not all complaints. Occasionally viewers are happy about something and call with an "appreciation" as they are known in the business. Like the chap who rang C4 to tell them: "Jon Snow - absolutely brilliant. He comes across very well and doesn't piss off his interviewees like, say, Paxman does. He asks the questions that we would ask ourselves and wears great ties. Brilliant."

And others just want to impart valuable intelligence. Such as the observant citizen who rang BBC News 24 three times to point out that a peasant in the background of a report from Afghanistan by Mike Sergeant was, in fact, Osama bin Laden.